Body fluids are useful for detecting substances of diagnostic interest. These substances may be present at relatively high concentrations in the blood for example, so that they can easily be detected there. Other substances accumulate in the urine, which additionally has the advantage that it is easier to collect for analysis purposes. Moreover, many substances such as antibodies, antigens, pharmaceutical active substances and naturally occurring hormones, and also drugs, for example cocaine, can be detected in saliva. For detecting the relevant substances, a number of quick tests have been developed which in many cases are based on a single test strip through which the sample of fluid moves and, in the presence of a substance to be detected, triggers a color reaction for example.
Various devices for collecting samples of suitable fluids are known. In the simplest case, a test strip can for example be brought into direct contact with the sample of fluid, or, as is described in DE 198 30 405 A1, the test strip can be provided with a flexurally stiff holder for the test strip in order to protect said test strip from mechanical stresses. However, corresponding devices are in most cases not suitable for collecting saliva for example, the reason being that, in order to avoid direct contact with the analysis reagents in the test strip, they cannot be placed directly in the mouth. In addition, an undefined amount of sample is taken up by the test strip, so that fluctuations in the amount of sample taken up can lead to different measurement results.
A device for collecting saliva by means of an absorbent pad is disclosed in EP-A-0 418 739. This device comprises an absorbent pad which by means of a holder is introduced into the mouth. After the absorbent pad has taken up the saliva, it has to be stored in a separate container until such time as it is further tested. To do so, the absorbent pad can be separated from the holder by means of a special device. The device described for collecting saliva consists of several individual parts which have to be handled separately. In addition, there is a possibility that the person taking the sample will come into undesirable contact with the saliva sample from the person being tested or will inadvertently contaminate the sample. Finally, it is difficult for the person taking the sample to know whether the absorbent pad has taken up a sufficient amount of saliva. This may be of particular importance if, as a result of drug consumption, the person being tested has a reduced flow of saliva or refuses to cooperate willingly with the person taking the sample.
To ensure that a sufficient amount of saliva has been taken up into the absorbent pad of a device for collecting saliva, U.S. Pat. No. 5,714,341 proposes providing the absorbent pad with a further absorbent part in the handle of the device, said further absorbent part containing an indicator substance. When the absorbent pad is saturated with saliva, the saliva also spreads into the additional absorbent part of the device and there transports a dye to a viewing window, by which means a sufficient saturation of the absorbent pad with saliva is displayed. However, this has the disadvantage that the person being tested may potentially come into contact with the dye. In addition, the disclosed device for collecting saliva requires a separate device for detecting the desired analyte, so that the person taking the sample may come into contact with the saliva of the person being tested and, as a whole, the test is awkward to manage.
U.S. Pat. No. 5,479,937 discloses a device for collecting saliva in which an absorbent pad is secured on the plunger of a syringe and the pad, saturated with saliva when removed from the mouth, is squeezed out by means of the plunger in a syringe body in order to obtain the saliva. U.S. Pat. No. 4,774,962 proposes using centrifugation to obtain the saliva collected in an absorbent pad placed in the mouth of the person being tested. According to U.S. Pat. No. 4,418,702, the saliva is to be squeezed out from a corresponding saliva-saturated pad by means of a special screw device.
The above-described devices for collecting saliva have the disadvantage that they consist of a plurality of individual parts. This makes handling difficult especially for routine tests. In addition, having to handle a plurality of individual parts means that the person taking the sample can easily come into contact with the saliva-saturated pad. This is undesirable from the point of view of the person taking the sample and compromises the acceptance of corresponding routine tests, for example by the police. In addition, the complicated handling may lead to undesired contamination of the sample. Finally, with the known devices, it is difficult to obtain an easily reproducible amount of saliva and make this available for a subsequent test.
It is therefore an object of the present invention to make available a device for collecting samples of fluids, in particular of body fluids such as saliva, which permits safe, simple and hygienic handling even by untrained persons. In addition, there should be little chance of the person taking the sample coming into contact with the sample of fluid which has been taken up. The device is also intended to permit a quick test for a desired analyte without a plurality of individual parts having to be handled separately from one another. The sample should be collected and made available for the test in an amount that is as reproducible as possible. Finally, checking whether enough sample material has been taken up by the device should be easy to do, even when an untrained person is taking the sample.